1. Field of the Invention
This invention relates to lubricant compositions and, more particularly, to lubricant compositions in the form of oils of lubricating viscosity and greases containing such oils as vehicles and wherein these lubricants are contaminated by undesirable quantities of water which have an accelerating effect on metal fatigue.
2. Description of the Prior Art
Lubricant compositions, such as oils and greases, are often found to contain appreciable quantities of water, resulting in a deleterious effect on the fatigue life of metals, such as bearings, gears and other moving machinery parts. The presence of such contaminating quantities of water if found to result from condensation occasioned by heat and subsequent cooling of the lubricant in the course of performing its function. In many instances, the presence of water may be found in the lubricant in amounts as much as from 0.01% to about 5%, by weight. The ability, therefore, to provide an effective additive to counteract the accelerating effect of water in the lubricant on metal surfaces is therefore highly desirable.
No prior art is known which discloses the lubricant compositions of this invention. This is not surprising, since metal fatigue and its prevention are very special problems. Consequently, few good additives having anti-fatigue properties are known.
U.S. Pat. No. 3,184,474 teaches a lubricant composition containing a product made from alkenyl succinic acid or anhydride, a polyhydric material and a polyamine. The differences between this product and that of the present application are clear. Since patentee was dealing with polyfunctional alcohols and amines, the final product had to be a complex mixture of materials. Furthermore, the reaction with the polyamine produced an amide. In contrast, the product of the present invention contains no complex mixture. It involves a single ester and a simple acidamine salt.
U.S. Pat. No. 2,830,021 teaches mineral oil composition containing aliphatic amine salts of monoalkyl esters of dimers of dienoic and trienoic fatty acids. Finally, U.S. Pat. No. 2,689,828 concerns mineral oils containing the amine salt of an aliphatic half ester of phthalic or alkyl-substituted phthalic acid.